Silica nanoparticle dispersions in homopolymer versus block copolymer

2007 ◽  
Vol 45 (16) ◽  
pp. 2284-2299 ◽  
Author(s):  
Qiang Lan ◽  
Lorraine F. Francis ◽  
Frank S. Bates
Keyword(s):  
Block Copolymer ◽  
Silica Nanoparticle ◽  
Nanoparticle Dispersions ◽  
Versus Block

Mesoporous silica/nanoparticle composites prepared by 3-D replication of highly filled block copolymer templates

2014 ◽  
Vol 2 (29) ◽  
pp. 5938-5943 ◽  
Author(s):  
Nicholas R. Hendricks ◽  
Rohit Kothari ◽  
Xinyu Wang ◽  
James J. Watkins
Keyword(s):  
Hydrogen Bonding ◽  
Block Copolymer ◽  
Mesoporous Silica ◽  
Silica Nanoparticle ◽  
Mesoporous Silica Nanoparticle ◽  
Nanoparticle Composites

Nanoparticle/mesoporous silica composites were created with high loadings of nanoparticles via selective hydrogen bonding between nanoparticles and block copolymer templates.

CURE KINETICS AND FINAL PERFORMANCE OF STYRENE BUTADIENE STYRENE BLOCK COPOLYMER/SILICA NANOCOMPOSITES

2015 ◽  
Vol 88 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Ahmad Moaddab ◽  
Mohammadreza Kalaee ◽  
Saeedeh Mazinani ◽  
Ali Aghajani ◽  
Mohammad M. Rajab
Keyword(s):  
Block Copolymer ◽  
Silica Nanoparticle ◽  
Cure Kinetics ◽  
Test Methods ◽  
Force Microscopy ◽  
Silica Nanocomposites ◽  
Final Performance ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

ABSTRACT Cure kinetics and the final performance of styrene–butadiene–styrene block copolymer (SBS)/silica nanocomposites followed by vulcanization are analyzed. The results indicated that the presence of silica affects the curing reaction of SBS, and additional heating is required for complete vulcanization of SBS/silica nanocomposites due to their higher activation energy. The samples were characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy, atomic force microscopy, and tensile test methods. The tensile strength, hardness, and wear resistance of SBS/silica nanocomposites show considerable increases by incorporating different silica nanoparticle contents in the SBS matrix; however, silica nanoparticles cause a decrease in modulus and elongation at break compared to cured neat SBS.

scholarly journals Molecular Assembly in Block Copolymer-Surfactant Nanoparticle Dispersions: Information on Molecular Exchange and Apparent Solubility from High-Resolution and PFG NMR

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3265
Author(s):  
Guilherme A. Ferreira ◽  
Watson Loh ◽  
Daniel Topgaard ◽  
Olle Söderman ◽  
Lennart Piculell
Keyword(s):  
Block Copolymer ◽  
Aqueous Media ◽  
Particle Surface ◽  
Molecular Assembly ◽  
The Self ◽  
Self Diffusion ◽  
Nanoparticle Dispersions ◽  
Complex Salts ◽  
D Values ◽  
Pfg Nmr

Internally structured block copolymer-surfactant particles are formed when the complex salts of ionic-neutral block copolymers neutralized by surfactant counterions are dispersed in aqueous media. Here, we report the 1H NMR signal intensities and self-diffusion coefficients (D, from pulsed field gradient nuclear magnetic resonance, PFG NMR) of trimethyl alkylammonium surfactant ions and the poly(acrylamide)-block-poly(acrylate) (PAAm-b-PA) polyions forming such particles. The results reveal the presence of an “NMR-invisible” (slowly exchanging) fraction of aggregated surfactant ions in the particle core and an “NMR-visible” fraction consisting of surface surfactant ions in rapid exchange with the surfactant ions dissociated into the aqueous domain. They also confirm that the neutral PAAm blocks are exposed to water at the particle surface, while the PA blocks are buried in the particle core. The self-diffusion of the polyions closely agree with the self-diffusion of a hydrophobic probe molecule solubilized in the particles, showing that essentially all copolymer chains are incorporated in the aggregates. Through centrifugation, we prepared macroscopically phase-separated systems with a phase concentrated in particles separated from a clear dilute phase. D values for the surfactant and block copolymer indicated that the dilute phase contained small aggregates (ca. 5 nm) of surfactant ions and a few anionic-neutral block copolymer chains. Regardless of the overall concentration of the sample, the fraction of block copolymer found in the dilute phase was nearly constant. This indicates that the dilute fraction represented a tail of small particles created by the dispersion process rather than a true thermodynamic solubility of the complex salts.

scholarly journals Printing spongy all-in-liquid materials

2021 ◽  
Author(s):  
Parisa Bazazi ◽  
Howard Stone ◽  
S. Hossein Hejazi
Keyword(s):  
3D Structure ◽  
Silica Nanoparticle ◽  
Simple Approach ◽  
Scaling Analysis ◽  
Nanoparticle Dispersions ◽  
Spongy Texture ◽  
Liquid Systems ◽  
Flexible Walls ◽  
Oil Water

Abstract Printing structured networks of functionalized droplets in a liquid medium enables engineering collectives of living cells for functional purposes [1, 2], bacterial ecology [3], and promises enormous applications in processes ranging from energy storage [4, 5] to drug delivery [6, 7]and tissue engineering [8]. Current approaches are limited to drop-by-drop printing [1, 2] or face limitations in reproducing the sophisticated internal features of a structured material and its interactions with the surrounding media [6, 9–11]. Here, we report on a simple approach for creating stable liquid filaments of silica nanoparticle dispersions and use them as inks to print all-in-liquid materials that consist of a network of droplets. Silica nanoparticles stabilize liquid filaments at Weber numbers two orders of magnitude smaller than previously reported in liquid-liquid systems by rapidly producing a concentrated microemulsion zone at the oil-water interface. We experimentally demonstrate that the printed aqueous phase is emulsified in-situ; consequently, a 3D structure is achieved with flexible walls consisting of layered microemulsions. The tube-like printed features have a spongy texture resembling miniaturized versions of “tube sponges” found in the oceans. A scaling analysis based on the interplay between hydro-dynamics and emulsification kinetics reveals that liquid filaments are formed when emulsions are generated and remain at the interface during the printing period. We demonstrate the utilization of filaments of the nanoparticle dispersions for printing fluidic channels and propose to use them as lab-on-a-chip devices.

Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

Wettability alteration of sandstones by silica nanoparticle dispersions in light and heavy crude oil

2017 ◽  
Vol 19 (9) ◽  
Author(s):  
Britta M. J. Huibers ◽  
Ashley R. Pales ◽  
Lingyun Bai ◽  
Chunyan Li ◽  
Linlin Mu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Silica Nanoparticle ◽  
Wettability Alteration ◽  
Heavy Crude Oil ◽  
Nanoparticle Dispersions ◽  
Heavy Crude

The Viscosity of Silica Nanoparticle Dispersions in Permeable Media

2013 ◽  
Vol 16 (03) ◽  
pp. 327-332 ◽  
Author(s):  
Cigdem Metin ◽  
Roger T. Bonnecaze ◽  
Quoc P. Nguyen
Keyword(s):  
Porous Media ◽  
Oil And Gas ◽  
Low Cost ◽  
Silica Nanoparticle ◽  
Oil And Gas Industry ◽  
Packing Fraction ◽  
Flow In Porous Media ◽  
Nanoparticle Dispersion ◽  
Nanoparticle Dispersions ◽  
Permeable Media

Summary The potential application of nanoparticle dispersions as formation-stimulation agents, contrast agents, or simply as tracers in the upstream oil and gas industry requires knowledge of the flow properties of these nanoparticles. The modeling of nanoparticle transport in hydrocarbon reservoirs requires a comprehensive understanding of the rheological behavior of these nanofluids. Silica nanoparticles have been commonly used because of their low-cost fabrication and cost-effective surface modification. The aqueous silica-nanoparticle dispersions show Newtonian behavior under steady shear measurements controlled by a rheometer, as discussed by Metin et al. (2011b). The viscosity of nanoparticle dispersions depends strongly on the particle concentration, and that this correlation can be depicted by a unified rheological model (Metin et al. 2011b). In addition, during flow in permeable media, the variation of shear associated with complex pore morphology and the interactions between the nanoparticles and tortuous flow channels can affect the viscosity of nanoparticle dispersion. The latter is particularly important if the concentration of nanoparticles in dispersion may change because of nanoparticle adsorption on mineral/fluid and oil/water interfaces or by mechanical trapping of nanoparticles. In this paper, the flow of silica-nanoparticle dispersions through different permeable media is investigated. The rheological behaviors of the dispersions are compared with those determined by use of a rheometer. We established a correlation between the nanoparticle concentration and dispersion viscosity in porous media for various nanoparticle sizes. The effects of pore structure and shear rate are also studied. We have confirmed that the concept of effective maximum packing fraction can be applied to describe the viscosity of aqueous nanoparticle dispersions in both bulk flow and flow in porous media with high permeability and regular pore structures, but not at low permeability because of mechanical trapping. Our work provides new insight to engineering nanoparticle rheology for subsurface applications.

Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

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